Double writes on publish, causes R2R task failure

I don’t know if this is related to #3257, but I was able to repro this issue again using the latest Preview9 bits (8e9948a3b768811ca5b3a666ff06207a16be69ec, 3.0.100-preview9-013692).

Here’s the repro:

1. clone https://github.com/aspnet/Benchmarks (commit hash for repro: 3ddf6558ec4d3636dc8fec4f0c142834ffa38bf5)
2. dotnet publish -f netcoreapp3.0 -r win-x64 -v n src\BenchmarksServer /bl

There are 3 files double-written:

• Dia2Lib.dll
• TraceReloggerLib.dll
• OSExtensions.dll.

I’ll attach the binlog.

Also, this causes the R2R task to fail with errors like this one, if you add /p:PublishReadyToRun=true to the publish command:

e:\dotnet_preview9\sdk\3.0.100-preview9-013692\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Publish.targets(308,28): error MSB4094: "C:\Users\fadim\.nuget\packages\microsoft.diagnostics.tracing.traceevent\2.0.44\lib\netstandard1.6\OSExtensions.dll;C:\Users\fadim\.nuget\packages\microsoft.diagnostics.tracing.traceevent\2.0.44\lib\netstandard2.0\OSExtensions.dll" is an invalid value for the "CompilationEntry" parameter of the "RunReadyToRunCompiler" task. Multiple items cannot be passed into a parameter of type "Microsoft.Build.Framework.ITaskItem". [D:\GIT\Benchmarks\src\BenchmarksServer\BenchmarksServer.csproj]

[nguerrera]

My proposal would be to dedupe resolvedfiletopublish pre-Crossgen,bundler,linker with last one wins to preserve same output as today. And warn if any dupes are removed. Any warning would still be a bug, but not blocking, and come to us rather than you.

[marcpopMSFT]

Daniel thinks this is probably fixed.